Tamperproof closure

ABSTRACT

A tamperproof closure adapted to be fitted on a container by a rotary motion of the closure, for example by means of threads, includes an inner cap having internal means for engaging the container, and an outer cap surrounding the inner cap. The outer cap has an aperture aligned with a projection extending from the end wall of the inner cap, so that the end walls of the caps are normally separated, but may be pushed together by forcing the projection through the aperture. When the caps are forced together suitable engaging means on the caps permit the caps to be rotated together. The projection is shaped to inhibit its withdrawal from the aperture once the caps have been forced together.

United States Patent [1 1 McIntosh TAMPERPROOF CLOSURE [75] Inventor:James A. McIntosh, Upper Montclair, NJ.

[73] Assignee: Mack-Wayne Plastics Company,

Wayne, NJ.

I22] Filed: Apr. 24, 1972 [2|] Appl. No.: 246,968

[52] U.S. Cl. 215/9 [51 Int. Cl 365d 55/02 [58] Field of Search 215/9,46 R [56] References Cited UNITED STATES PATENTS 3,685,676 8/1972 Gachet al. 215/9 3,520,435 7/1970 Mclntosh 215/9 Sept. 4, 1973 [5 7 ABSTRACTA tamperproof closure adapted to be fitted on a container by a rotarymotion of the closure, for example by means of threads, includes aninner cap having internal means for engaging the container, and an outercap surrounding the inner cap. The outer cap has an aperture alignedwith a projection extending from the end wall of the inner cap, so thatthe end walls of the caps are normally separated, but may be pushedtogether by forcing the projection through the aperture. When the capsare forced together suitable engaging means on the caps permit the capsto be rotated together. The projection is shaped to inhibit itswithdrawal from the aperture once the caps have been forced together.

10 Claims, 9 Drawing Figures I Z3 K30 TAMPERPROOF CLOSURE This inventionrelates to closures for containers, such as bottles or the like, inwhich the closure is adapted to engage and be held on the container as aresult of a relative rotary motion between the closure and thecontainer. Conventionally, of course, such caps employ suitable threadsfor engaging threads on the container. The invention is specificallydirected to the provision of a cap of this type which also includes anouter member surrounding the inner cap for inhibiting rotation of theinner cap, but being capable of manipulation to a position of mutualengagement so that the inner cap may be rotated by rotation of the outermember.

Closures of the above type have been employed in the past, and anexample of such a closure is disclosed in my US. Pat. No. 3,520,435,which issued on July 14, I970. As noted in the disclosure of myaforementioned patent, there are many products in daily use in modernhouseholds which may be harmful or dangerous when taken internally, sothat conventional screw-on type of caps present a hazard in householdswhere small children have access to the containers. It is of course nosolution to this problem to advise people to place the containers ininaccessible locations. As a consequence, numerous forms of tamperproofclosures have been suggested, as exemplified by my above mentionedpatent.

Another problem also exists with respect to the provision of closuresfor containers, whether they be tamperproof or not. Containers ofvarious materials, both harmful and nonharmful, and including somefoodstuffs, are frequently openly displayed on the shelves of stores.Unfortunately, in view of the ready accessibility of these containers,it has been noted on some occasions that employees of the premises aswell as customers occasionally open the containers for the purpose ofsampling or use, and then return the partially emptied containers to theshelves. Subsequent purchasers of the partially emptied containers arefrequently unaware of the tampering with the container they havepurchased, and do not obtain the full value for their money. Thepossibility also arises that prior opening of the containers may resultin the spoiling of the product.

In order to overcome this problem, it is further desirable to provide aclosure which will provide a good indication to a purchaser of whetheror not it has been tampered with. This problem can of course be overcomeby the use of various seals,:but many such tamperproof arrangementsunnecessarily increase the expense in producing the closure member.

It is therefore the object of this invention to provide an inexpensiveand easily manufactured tamperproof closure for a container, in whichthe operation of the closure by, for example, children, will bedifficult, and in which the fact that the closure has been tampered withis normally readily visible.

Briefly stated, in accordance with my invention, I provide a tamperproofclosure comprised of an inner cap and an outer cap. The inner cap has atop wall with a cylindrical skirt extending therefrom, the internalsurface of the inner cap having a configuration, such as threads,permitting the inner cap to be firmly held on the neck surrounding anopening in a container. The outer cap also has a top wall and acylindrical skirt extending therefrom. The outer cap is positioned sothat its cylindrical skirt radially surrounds the cylindrical skirt ofthe inner cap, and means are provided for permitting limited relativeaxial movement between the inner and outer caps, while inhibiting totalseparation of the caps. In the preferred embodiment of the invention,the inhibiting means is in the form of an annular bead extendinginwardly from the bottom of the cylindrical skirt of the outer cap, toengage the bottom of the cylindrical skirt of the inner cap.

A projection is provided on the top wall of the inner cap and extendingtoward the outer cap, and an aperture is provided in the top wall of theouter cap aligned with the projection. The projection preferably has around cross section, with its top of greater diameter than the diameterof the aperture, and its base diameter less than or equal to thediameter of the aperture. The projection thereby holds the two capsspaced apart, but the caps may be forced together so that the projectionextends through the aperture. The inner and outer caps are provided withmutually engagable means, such as lugs, which are out of engagement topermit free rotation of the outer cap with respect to the inner cap whenthe top walls thereof are spaced apart by the projection, but whichengage when the outer cap is forced downwardly onto the lower cap sothat the projection extends through the aperture, thereby permittingrotation of the inner cap by manual rotation of the outer cap.

By providing an outer cap that is normally freely rotatable with respectto the inner cap, the closure device according to my invention inhibitsopening of the closure device by persons not aware of the necessity forurging the projection through the aperture, such as small children. Inaddition, when the projection extends through the aperture, it isclearly evident that the closure has been tampered with. The projectionis shaped so that its withdrawal from the aperture is inhibited once thecaps have been forced together.

The invention will now be described in greater detail with reference tothe accompanying drawings, in which:

FIG. 1 is a perspective view of a closure device according to theinvention in place on the neck of a container;

FIG. 2 is a cross sectional view of a closure device according to apreferred embodiment of my invention, with the top walls of the innerand outer caps being separated by the projection to inhibit rotation ofthe inner cap, the cross section being parallel to the axis of thedevice; t

FIG. 3 is a cross sectional view of apreferred embodiment of a closureaccording to the invention, differing from the view of FIG. 2 in thatthe projection in the top wall of the inner cap has been forced throughthe aperture in the top wall of the outer cap to permit rotation of theinner cap;

FIG. 4 is a cross sectional view taken along the lines 4-4 of FIG. 3,and illustrating the engagement between the engaging means of the innerand outer caps;

FIG. 5 is a cross sectional view of a portion of a modification of theclosure of FIGS. 2 and 3;

FIG. 6 is a cross sectional view of a portion of another modification ofthe closure of FIGS. 2 and 3;

FIG. 7 is a cross sectional view of a portion of still anothermodification of the closure of FIGS. 2 and 3;

FIG. 8 is a cross sectional view of a further modification of a portionof the closure of FIGS. 2 and 3; and 7 FIG. 9 is a cross sectional viewof a still further modification of a portion of the closure of FIGS. 2and 3.

Referring now to the drawings, and more in particular to FIG. I, thereinis illustrated a closure device 10, according to the invention, inposition on the neck of a typical container 11. As is apparent in FIG.1, the only portions of the clsoure that are normally visible are anouter cap 12 having a top wall 13 with a central aperture 14, and acylindrical skirt 15 extending downwardly from the top wall 13 aroundthe neck of the container. The bottom of the aperture 14 is closed bythe top 16 of a projection, which will described in more detail in thefollowing paragraphs.

Referring now to FIG. 2, the closure according to the invention furthercomprises an inner cap 20 disposed within the outer cap 12, and coaxialtherewith. The inner cap has a top wall 21 aligned with the top wall 13of the outer cap, and a cylindrical skirt 22 extending from the top wall21 and radially surrounded by the cylindrical skirt 15 of the outer cap.The inner cap 20 is provided with a configuration, such as threads 23 onthe inside of the cylindrical skirt 22, to permit affixing of the innercap to suitable configurations, such as threads, on the neck of thecontainer 11 of FIG. 1. It will be understood, of course, that the formof the configuration for holding the inner cap onto the container doesnot form a part of the invention, and any configuration permitting theinner cap to be held on the container by virtue of at least a rotarymovement is contemplated, since as will be apparent in the followingparagraphs the closure is adapted to inhibit undesired rotary movementof the inner cap.

A centrally positioned projection 25 is provided on the top of the topwall 21 of the inner cap, and extending toward the top wall of the outercap. The projection 25 preferably has a round cross section. The base 26of the projection 25 has a diameter which is equal to or slightly lessthan the diameter of the aperture 14, while the top 16 of the projection25 has a diameter greater than the diameter of the aperture 14. Theprojection 25 and aperture 14 are centrally disposed, i.e. along theaxis of the closure, so that their alignment will be maintained withrelative rotation of the outer and inner caps. For example, theprojection may have an annular knob-like protrusion 27 at its uppermostportion. The projection 25 is intended to hold the top walls of theinner and outer caps in spaced apart positions as shown in FIG. 2, andif desired an annular recess 28 may be provided in the bottom of theaperture 14, against which the end 16 of the projection rests when .thecaps are in the spaced apart position.

It is of course desirable that the inner and outer caps be relativelyunseparable while permitting a limited axial movement therebetween. Forthis purpose, an annular inwardly extending head 30 is provided at thebottom of the cylindrical skirt 15 of the outer cap, the bead beingpositioned to engage the bottom of the cylindrical skirt 22 of the innercap when the top walls of the caps are in their spaced apart position asillustrated in FIG. 3. The bead 30 thereby prevents the top walls of thecaps from moving further apart, but permits their movement to a closertogether position. The provision of the annular head 30 is exemplaryonly, since such a configuration is easy to form in plastic members, andit will be understood that any conventional interengagement between theinner and outer caps which serves the above described function arecontemplated herein.

While the top of the projection 16 is of larger diameter than theaperture 14, in accordance with the invention the outer cap 12 is madeof a material which is sufficiently flexible and deformable to permitthe projection 25 to be forced through the aperture 14 upon theapplication of pressure to the upper cap. For example, it is preferredthat the outer cap be molded of a conventional plastic material,especially since such materials are readily formed to the otherconfigurations of the cap. The requirements for materials of the innercap are not as demanding with respect to resilience, although the innercap is preferably molded from a similar material. Thus, the materialsemployed for the inner cap and the outer cap may be made in accordancewith the closure member disclosed in my above mentioned U.S. Pat. No.3,520,435.

FIG. 3 illustrates the closure of FIG. 2 in which the outer cap has beenforced downwardly so that the projection 25 extends therethrough. Inthis figure it is seen that the enlarged end 16 of the projectionextends beyond the aperture 14, to inhibit movement of the outer capback to its spaced apart position as illustrated in FIG. 2. The relativedimensions of the end 16 of the projection 25 and the aperture 14 aredependent upon the flexibility and deformability of the materialsemployed, and these dimensions should thus be selected so that thedownward movement of the outer cap is accomplished only with some degreeof difficulty. The recess 28 has been provided in order to permit adegree of freedom in the selection in the thickness of the top wall ofthe outer cap from the standpoints of strength and necessaryflexibility, while still permitting a reduction in the overalllongitudinal dimension of the closure. As illustrated in FIG. 3, whenthe outer cap has been forced down to the inner cap, the annular bead 30is moved to a position spaced from the bottom of the skirt 22 of theinner cap.

The closure according to the invention is arranged so that the outer cap12 is freely rotatable with respect to the inner cap 20 when the topwalls of the two caps are held apart by the projection 25 in theposition illustrated in FIG. 2, but that the inner cap and outer cap arerotatable together when the outer cap has been moved to the positionillustrated in FIG. 3. For this purpose, according to one embodiment ofthe invention, as illustrated in FIGS. 2 and 3, inwardly extending ribs35 are provided inside the cylindrical skirt 15 of the outer cap, andoutwardly extending ribs 36 are provided on the outer surface of thecylindrical skirt 22 of the inner cap. A plurality of such ribs 35 and36 may be provided around the'circumference of the cylindrical skirts asillustrated in FIG. 4. The ribs 35 and 36 are positioned on theirrespective cylindrical skirts so that they are axially separated whenthe inner and outer caps are held apart as illustrated in FIG. 2, butare mutually engagable when the inner and outer caps are moved togetheras illustrated in FIG. 3. In the embodiment of my invention illustratedin FIGS. 2 and 3, the ribs 36 are adjacent the bottom of the skirt 22 ofthe inner cap, extending upwardly from an outwardly extending annularhead 37 at the bottom of the cylindrical skirt 22. The bottom of thecylindrical skirt 15 has a diameter, as illustrated at 38, to permitclearance of the ribs 36, while the upper portion 39 of the outer caphas a slightly reduced diameter to permit clearance with the upperportion of the cylindrical skirt of the inner cap. The ribs 35 areprovided in the central region of the cylindrical skirt between theportions 38 and 39 thereof. The ribs 35 and 36 are preferably relativelynarrow in the circumferential direction, and are spaced apart, so thatthey do not inhibit movement of the outer cap to the positionillustrated in FIG. 3. As an example, it has been found that from 5 to10 such ribs in each cap are adequate.

In the assembly of the closure according to my invention, it ispreferred that the inner cap first be placed on the neck of thecontainer and rotated to seal the neck of the container. Since the outercap is of a flexible material, the outer cap may then be placed over thetop of the inner cap, and the flexibility of the member will permit thewalls of the outer cap to be flexed outwardly as the outer cap is forceddownwardly until a position at which the annular bead 30 just snaps overthe bottom of the cylindrical skirt 22. The outer cap should not beforced downwardly further than this, so that the projection 25 is neverforced through the aperture 14 until the contents of the container areready for use.

The closure of the invention may of course include sealing means, suchas sealing rings integrally molded in the inner cap, if desired.

As illustrated in FIG. 3, inspection of a container incorporating atamperproof cap according to the invention will readily reveal that theclosure has been tampered with, since in this case the projection 25will extend through the aperture 14 and be readily visible at the top ofthe closure.

In order to provide tamperproof characteristics in the arrangementaccording to the invention, it is preferred that the components of thetamperproof cap be shaped to inhibit the removal of the projection 25from the aperture once the outer cap has been forced downwardly. Thus,the top of the aperture 14 is as small as possible with respect to thediameter of the projection to provide a close fit, and the underside ofthe enlarged end 16 of the projection is formed as flat as possible, asdetermined by the molding techniques employed in the fabrication of themember, so that withdrawal of the projection from the aperture is asdifficult as possible. In addition, withdrawal of the projection fromthe aperture is inhibited by the fact that when the outer cap is forceddownwardly, the bottom of the outer cap is at its closest position tothe container 11, so that it is difficult to get enough purchase on thebottom of the outer cap with the fingers to apply sufficient force onthe outer cap to effect the removal of the projection from the aperture.Movement of the outer cap in the downward direction, however, isfacilitated, for example, by providing a chamfer in the lower portion ofthe aperture, such as the annular recess 28, and by forming the top ofthe enlarged end 16 with as close to a full round surface as possible,at least in the portion thereof which engages the aperture. In addition,it is much easier to force the outer cap downwardly since there is amplesurface on the top of the outer cap surrounding the aperture to enablethe user to apply the necessary force thereto.

While as above stated it is preferred that the projection 25, and hencethe aperture 14, have round cross sections, it is also contemplated thatirregular cross sections may be permitted for the projection andaperture so that the irregular surfaces thereof can engage upon movementof the outer cap to the position illustrated in FIG. 3, and therebypermit rotation of the inner cap by virtue of the engagement of theaperture 14 and the projection 25. In such case the lugs or othersimilar engaging means may of course be dispensed with if desired, andthe diameters of the projection 25 and hence the aperture 14 should beincreased to permit the application of the necessary rotary force to theinner cap.

Referring now to FIG. 5, therein is illustrated a modification of theclosure of FIGS. 3 and 4 with respect to the ribs provided for mutualrotation of the inner and outer caps. In this arrangement, the inner capis provided with spaced apart longitudinally extending ribs 40 of thesame general form as illustrated in FIGS. 3 and 4, but extendingupwardly toward the top wall of the inner cap for a greater distance,but not completely to the top of the inner cap. The outer cap asillustrated in FIG. 5 is of substantially equal diameter throughout itslength, and internal ribs 41 are provided extending from the top wall 13downwardly pass the top of the top wall of the inner cap but not so faras the ribs 40. When the inner and outer caps are spaced apart in theposition illustrated in FIG. 5, the ribs 40 and 41 are axiallyseparated, so that the outer cap can rotate freely, but the lower edgesof the ribs 41 engage the upper edges of the ribs 40 when the outer capis moved to its lowermost position, to permit mutual rotation of theinner and outer caps.

In the embodiment of the invention illustrated in FIG. 6, the ribs 43 onthe outside of the inner cap extend throughout the length of the innercap, while the longitudinal ribs 44 on the inside surface of thecylindrical skirt of the outer cap do not extend downwardly as .far asthe top of the inner cap when the inner and outer caps are in theirseparated position as illustrated in FIG. 6. When the outer cap is moveddownwardly, the ribs 44 engage the ribs 43 to permit mutual rotation ofthe inner and outer caps.

In the further embodiment of FIG. 7, instead of providing ribs on theinner cap, the top of the inner cap may be provided with shortlongitudinally extending recesses 45, while the inside surface of theouter cap is provided with longitudinally extending ribs 46 adapted toengage the recesses 45 when the outer cap is moved downwardly (notshown), but be separated when the outer cap is held to its uppermostposition by the projection 25.

In still another embodiment of the invention, as illustrated in FIG. 8,instead of providing the ribs as in the above examples of the invention,the bottom of the top wall 13 of the outer cap may be provided withdownwardly extending projections 48 adapted to engage suitable recesses49 in the top of the top wall of the inner cap when the outer cap ismoved downwardly, but be separated therefrom when the outer cap is inits uppermost position as illustrated. The projections 48 and recesses49 may have circular cross section, in which case their mutual alignmentis required before fully moving the outer cap toward the inner cap.Alternatively, of course, the recesses may have triangular crosssections, with radially extending apices, the recesses being provided ina continuous configuration about the circumference of the top wall, withthe projections 48 having a similar cross section, to obviate thenecessity for close alignment of the inner and outer caps before movingthe outer cap downwardly toward the inner cap.

In a still further embodiment of the invention, the inside surface ofthe outer cap may be provided with ribs extending radially inwardly onthe bottom of the top wall 13 from the cylindrical skirt, the topcircumference of the top wall 21 being provided with radially inwardlyextending ribs or recesses 56, so that the ribs or recesses 56 and theribs 55 are mutually separated when the outer cap is held spaced apartfrom the inner cap by the projection 25, as illustrated, but mutuallyengaged for common rotation of the inner and outer caps when the outercap is moved downwardly toward the inner cap.

While the invention has been disclosed with reference to a limitednumber of embodiments, it will be obvious that many variations andmodifications may be made therein without departing from the spirit andscope of the invention, and it is therefore intended that the inventionas recited in the following claims cover all such variations andmodifications as may be obvious from the above disclosure.

What is claimed is:

1. In a safety closure for a container of the type having a cylindricalneck over which a closure is adapted to fit and be held, the closurebeing of the type having an inner cap which is securable over the neckof the container by a rotary motion, and an outer cap surrounding theinner cap for selectively inhibiting rotation of the inner cap, andwherein-engaging means are provided on the inner cap and outer cap formutual engagement in a first relative axial position of the inner andouter caps, and be separated at a second relative axial position of theinner and outer caps; the improvement wherein said inner cap comprises atop wall and a cylindrical skirt extending downwardly therefrom forengagement with a container, and said outer cap has a top wall alignedwith the top wall of said inner cap and having a cylindrical skirtextending therefrom and surrounding the cylindrical skirt of the innercap, said inner cap further having a projection extending from the topwall thereof toward the top wall of said outer cap, said outer capfurther having an axially extending aperture aligned with saidprojection, said projection having a base adjacent the top wall of saidinner cap that is no greater than the diameter of said aperture, saidprojection further having a diameter at its end away from said top wallof said inner cap that is greater than the diameter of said aperture,whereby said projection holds said outer cap spaced from said inner capin said second position and said projection may be forced through saidaperture to attain said first position.

2. A tamperproof closure for a container of the type having a threadedneck, said closure comprising an inner cap having a first top wall andan internally threaded first cylindrical skirt extending therefrom forengaging the threaded neck of the container, said closure furthercomprising an outer cap having a second top wall and a secondcylindrical skirt extending therefrom, said second skirt beingpositioned to surround said first skirt, a projection extending fromsaid first top wall toward said second top wall, a ap perture in saidsecond top wall aligned with said projection, said projection having abase portion adjacent said first top wall of smaller cross sectionaldimension than said aperture and an end portion of greater crosssectional dimension than said aperture, whereby said projection holdssaid second top wall in a first position spaced from said second topwall and said second top wall may be forced toward said first top wallwith said projection extending through said aperture to a secondposition, and engaging means on said inner and outer caps positioned topermit free relative rotation of said inner and outer caps in said firstposition and to transmit rotary movement from said outer cap to saidinner cap in said second position.

3. The tamperproof closure of claim 2 wherein said projection has acircular cross section and said aperture is round.

4. The tamperproof closure of claim 2 further comprising mutuallyengaging means on said inner and outer caps inhibiting separation ofsaid inner and outer caps beyond said first position.

5. The tamperproof closure of claim 4 wherein said mutually engagingmeans comprises an annular inwardly extending bead at the bottom of saidsecond cylindrical skirt for engaging the bottom of said firstcylindrical skirt.

6. The tamperproof closure of claim 2 wherein said engaging meanscomprises axially extending ribs on the outer circumference of saidfirst cylindrical skirt, and axially extending ribs on the inner surfaceof said second cylindrical skirt.

7. The tamperproof closure of claim 6 wherein the ribs on said firstcylindrical skirt extend outwardly from the bottom edge of said firstcylindrical skirt, and the ribs on said second cylindrical skirt extenddownwardly from said second top wall.

8. The tamperproof closure of claim 2 wherein said engaging meanscomprises radially extending ribs on the top of said first top wall andradially extending ribs on the bottom of said second top wall.

9. The tamperproof closure of claim 2 wherein said engaging meanscomprises projection means extending from said second top wall towardsaid first top wall, and recess means in said first top wall alignablewith said projections in said second top wall.

10. The tamperproof closure of claim 2 wherein said second top wallfurther includes a recess surrounding said aperture on the side thereoftoward said first wall, whereby said projection engages said recess insaid first position.

i l i t

1. In a safety closure for a container of the type having a cylindricalneck over which a closure is adapted to fit and be held, the closurebeing of the type having an inner cap which is securable over the neckof the container by a rotary motion, and an outer cap surrounding theinner cap for selectively inhibiting rotation of the inner cap, andwherein engaging means are provided on the inner cap and outer cap formutual engagement in a first relative axial position of the inner andouter caps, and be separated at a second relative axial position of theinner and outer caps; the improvement wherein said inner cap comprises atop wall and a cylindrical skirt extending downwardly therefrom forengagement with a container, and said outer cap has a top wall alignedwith the top wall of said inner cap and having a cylindrical skirtextending therefrom and surrounding the cylindrical skiRt of the innercap, said inner cap further having a central projection extending fromthe top wall thereof toward the top wall of said outer cap, said outercap further having an axially extending aperture aligned with saidprojection, said projection having a base adjacent the top wall of saidinner cap that is no greater than the diameter of said aperture, saidprojection further having a diameter at its end away from said top wallof said inner cap that is greater than the diameter of said aperture,whereby said projection holds said outer cap spaced from said inner capin said second position and said projection may be forced through saidaperture to attain said first position.
 2. A tamperproof closure for acontainer of the type having a threaded neck, said closure comprising aninner cap having a first top wall and an internally threaded firstcylindrical skirt extending therefrom for engaging the threaded neck ofthe container, said closure further comprising an outer cap having asecond top wall and a second cylindrical skirt extending therefrom, saidsecond skirt being positioned to surround said first skirt, a centralprojection extending from said first top wall toward said second topwall, a central aperture in said second top wall aligned with saidprojection, said projection having a base portion adjacent said firsttop wall of smaller cross sectional dimension than said aperture and anend portion of greater cross sectional dimension than said aperture,whereby said projection holds said second top wall in a first positionspaced from said second top wall and said second top wall may be forcedtoward said first top wall with said projection extending through saidaperture to a second position, and engaging means on said inner andouter caps positioned to permit free relative rotation of said inner andouter caps in said first position and to transmit rotary movement fromsaid outer cap to said inner cap in said second position.
 3. Thetamperproof closure of claim 2 wherein said projection has a circularcross section and said aperture is round.
 4. The tamperproof closure ofclaim 2 further comprising mutually engaging means on said inner andouter caps inhibiting separation of said inner and outer caps beyondsaid first position.
 5. The tamperproof closure of claim 4 wherein saidmutually engaging means comprises an annular inwardly extending bead atthe bottom of said second cylindrical skirt for engaging the bottom ofsaid first cylindrical skirt.
 6. The tamperproof closure of claim 2wherein said engaging means comprises axially extending ribs on theouter circumference of said first cylindrical skirt, and axiallyextending ribs on the inner surface of said second cylindrical skirt. 7.The tamperproof closure of claim 6 wherein the ribs on said firstcylindrical skirt extend outwardly from the bottom edge of said firstcylindrical skirt, and the ribs on said second cylindrical skirt extenddownwardly from said second top wall.
 8. The tamperproof closure ofclaim 2 wherein said engaging means comprises radially extending ribs onthe top of said first top wall and radially extending ribs on the bottomof said second top wall.
 9. The tamperproof closure of claim 2 whereinsaid engaging means comprises projection means extending from saidsecond top wall toward said first top wall, and recess means in saidfirst top wall alignable with said projections in said second top wall.10. The tamperproof closure of claim 2 wherein said second top wallfurther includes a recess surrounding said aperture on the side thereoftoward said first wall, whereby said projection engages said recess insaid first position.